Teeter terminal clamp



April zs, 1910 Unted States Patent O 3,509,521 TEETER TERMIN AL CLAMP Charles E. Gutshall, Roselle, lll., assignor to Illinois Tool Works Inc., Chicago, Ill., a corporation of Delaware Filed Oct. 3, 1968, Ser. No. 764,695 Int. Cl. H01r 7/24 ILS. Cl. 339-246 7 Claims ABSTRACT OF THE DISCLOSURE Teeter type terminal clamp is formed by bending a generally square apertured sheet metal stamping along a line connecting a first pair of diagonal corners thereof so as to form an upper ridge portion upon Which the clamp can pivot to enable it to apply equal clamping force to a pair of conductors of widely varying sizes which are clamped by serrated surfaces on the bottom surface of the clamping plate. The work engaging portions of the device have a convex cross section as viewed along a line parallel to the ridge line and extend upwardly toward the remaining pair of diagonal corners. The curved shape of the clamping face insures that a large variation in wire sizes can be accommodated without the possibility of Sharp edges severing them.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to wire clamps and more particularly to an electrical terminal clamp to which one or more elongated electrical conductors may be detachably secured.

Description of the prior art This invention is an improvement upon my prior invention entitled, Diagonal Teeter Terminal Clamp, -which is described in U.S. Patent 3,178,675. In the prior art device disclosed in the aforementioned patent a generally square stamping is formed With a single bend about a diagonal. Although such a design permits the clamping plate to rock so as to apply equal pressure to each of a pair of conductors held thereby, it results in the pressure being applied to at least one of the conductors by only a single edge of the clamping plate and thus offers a relatively small amount of engagement with such wire. Furthermore, such engagement of a wire by the corner of the clamping plate presents some possibility of notching the wire so as to weaken it or perhaps to even sever it.

German Patent 828,865 discloses a terminal clamp with a ridge between opposing sides rather than between diagonal corners. The German design also has downwardly projecting edges on the clamping plate which would limit its capability for handling a wide variation in wire sizes and its ability to clamp stranded wire. French Patent 1,292,367 is somewhat different from the German patent in that it has three ridges. However, its usefulness would be limited for the reasons expressed relative to the German patent.

SUMMARY It is an object of this invention to provide a terminal clamp which will accommodate and firmly clamp a pair of either solid or stranded wires of greatly different diameters, or alternatively, clamp only a single wire.

It is yet another object of this invention to provide a terminal clamp which provides maximum clamping for a given size and thickness of clamping plate.

These objects are obtained by the terminal clamp of the present invention wherein a sheet metal stamping is provided with an aperture adapted to receive a threaded fastener member and is bent so as to assume a generally 3,509,521 Patented Apr. 28, 1970 ICC wavy configuration when viewed from one corner thereof. The clamping plate is bent downwardly so as to form an upwardly extending central ridge portion which connects a first pair of diagonally opposed corners thereof. The clamping plate has a generally curved portion extending from each side of the upwardly extending ridge. The curved, downwardly extending portions of the clamping plate have a curve which continues past their lowermost 'work engaging portions and then extends upwardly into a second pair of diagonal corners. The curves of the clamping plate are fairly gradual and of such a magnitude that the distance between a plane tangent to the central ridge portion which engages the underside of a threaded fastener and the plane passing through the lower work engaging surface of the clamping plate is approximately twice the thickness of the clamping plate. Furthermore, the diagonal corners which are not on the central ridge are relieved upwardly to such an extent that their upper surfaces lie approximately in a plane containing the pair of diagonal corners which do contain the central ridge. Since the clamping plate is bent about a diagonal it is significantly stronger than it would be if it was bent about a line parallel to one side. This is so since more material is present to absorb the forces applied during clamping. By relieving the corners of the clamping plate upwardly the clamping plate is capable of rocking so as to accommodate a large range of wire sizes but without any possibility of nicking or severing the wires through contact therewith by a sharp edge of the clamping plate.

In order to enable the clamping plate to achieve a firm hold on the terminal wires the clamping plate is serrated on its work engaging surface. The serrations preferably extend inwardly from the corners thereof which are perpendicular to the central ridge. The serrations are thus at a 45 angle to each of the sides of the clamping plate. This particular orientation makesxit unnecessary to orient the clamping plate in any special manner relative to the wires and makes it possible to clamp the wires equally well regardless of which side they are placed parallel to.

The foregoing and other objects, features and advantages, will be apparent from the following more particular description of a preferred embodiment thereof, aS illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing the relationship of the clamping plate of the invention With respect to an associated fastener and a pair of terminal wires and the terminal plate to which they are to be connected.

FIG. 2 is a side view of the clamping plate and associated fastener of the present invention from one corner thereof and taken along line 2-2 of FIG. 1;

FIG. 3 is a side view of the clamping plate and associated fastener of the present invention taken along line 3-3 of FIG. l;

FIG. 4 is a side view ofthe clamping plate of the present invention in operative engagement With the pair of different sized stranded wires taken in the direction of lines 4 4 of FIG. 1;

FIG. 5 is a bottom plan view of the clamping plate of the present invention; and

FIG. 6 is a perspective view similar to FIG. 1 of a modified form of clamping plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a clamping plate indicated generally at 2 is shown in exploded relationship relative to a pair of stranded conductors 4 and 6 which are adapted to be clamped thereby to a metal terminal strip 8 on a terminal block 10 by means of a threaded fastener 12. The clamping plate 2 is generally square and includes a first pair of diagonally opposed corners 14, 16 and a second pair of diagonally opposed corners 18, 20. The clamping plate has a top surface 22 and a bottom surface 24. As can be seen in FIGS. 1 and 2 the clamping plate12 is bent into a wavy symmetrical shape and includes a central ridge portion 26 which connects diagonally opposed corners 14, 16. The plate curves downwardlyv gently from the central ridge portion 16 so as to form a pair of curved work engaging portions 30, 32 on either side of the fastener 12. The curved work engaging surfaces 30, 32 are curved upwardly as they approach the diagonal corners 18, 20 so as to prevent the possibility of any corner or edge of the clamping plate 2 from engaging a conductor and possibly weakening it by nicking it or severing it through the application of too much pressure on fastener 12.

In order to permit the lower work engaging surfaces 30, 32 of the clamping plate to fiirmly engage the conductors 4, 6, the clamping plate is serrated slightly at the corners 18, 20. The serrations 36 are arranged at a 45 angle to the sides of the clamping plate. The 45 arrangement of the serrations makes them function equally well regardless of which direction parallel to the sides which the wires engage the clamping plate. For example, the clamping plate 2 in FIG. 1 will clarnp equally well in the position shown or when rotated 90 relative to the position shown.

In FIG. 6 a modifled form of clamping plate 2' similar to the clamping plate 2 in FIG. 1 is shown. The clamping plate 2' is identical to clamping plate 2 in that it has a generally square upper surface 22' and upwardly extending corners 14', 16', 18', as well as a corner diagonally opposed to corner 18' which corresponds to corner 20 of clamping plate 2. Clamping plate 2' differs from clamping plate 2 in that it has a pair of bent-over side portions 40, 42 which are adapted to eXtend down over a terminal plate member 8' so as to prevent sideways movement of conductors 4, 6 and to prevent the clamping plate from rotating while the fastener 12 is screwed down into terminal plate 8'. The bent-over side members 40, 42 thus perform the same function as the bent-up portions 44, 46 of terminal plate 8 in FIG. 1.

What is claimed is:

1. A clamping device for securing elongated members to a clamping plate comprising a sheet metal stamping having an apertured generally square portion andfastening means extending through the aperture, said generally square portion including an upwardly extending central ridge portion engageable with the underside of said fastening means and connecting a first pair of diagonal corners of said generally square portion, said generally square portion having a wavy symmetrical profile extending downwardly from either side of said central ridge portion to initially form a pair of work engaging portions and then extending upwardly towards a second pair of diagonal corners.

2. The clamping device of claim 1 wherein serrations are formed in said work engaging portions on the underside of said stamping.

3. The clamping device of claim 2 wheren said serrations are positioned generally perpendicularly to a line connecting said first pair of diagonal corners.

4. The clamping device of claim 1 wherein said first and second pairs of corners of said generally square portion lie in substantially the same plane.

, 5. The clamping device of claim 1 wherein the uppermost portion of the central ridge portion is spaced from a plane containing the lowermost portion of said pair of work engaging portions by a distance substantially equal to twice the thickness of said stamping.

6. The clamping device of claim 1 wherein said generrally square portion comprises the who-le of said starnping. i 7. The clamping device of claim 1 wherein said stamping comprises a pair of side portions extending generally at right angles to said square portion and in the direction of clamping from a pair of opposite edges of said square portion.

References Cited UNITED STATES PATENTS 3,178,675 4/1965 Gutshall 339-246 3,372,366 3/1968 COchrum 339-272 MARVlN A. CHAMPION, Primary 'Examiner J. H. MCGLYNN, Assistant Examiner U.S. Cl. XR. 

